Orthodontic expansion is an occasionally required dental procedure to provide additional spacing for the teeth of a person. Particularly, orthodontic expanders function to expand the midpalatine suture of a patient and thereby increasing the maxillary transverse dimension in patients with maxillary transverse hypoplasia. Current known orthodontic expanders each include a screw that upon rotation causes opposing portions of the expander to move apart. Legs extending from the expander attach to orthodontic bands engaged to teeth. The legs communicate the laterally outward force from the expander to the maxillary suture of the patient. The continued application for laterally outward force causes the transverse dimension to increase slowly.
While orthodontic expanders have accomplished the goals of increasing the maxillary transverse dimension, there are drawbacks to their use. The available devices can experience slippage from frictional torque failure by which the screws turn back or slip from a setpoint. This leads to lost treatment time and additional clinical visits. The patient experiences frustration with the treatment and the orthodontic practice invests time and labor that could otherwise be directed to other patients. Also, present screw devices lack accurate indicators of the amount of opening being experienced during treatment, in part due to slippage, but also to inaccurate rotation count by the patient during interim adjustments of the expansion device, and inexact intraoral measurements.
Another potential problem is over-opening the expansion device that can result in separation of the end of the screw from the expansion device. Separation requires removal and reinstallation of the expansion device typically on an emergency or rush basis. Further, separation can require a re-start of the expansion process after stabilization. At the conclusion of the expansion process, the expansion device must be held in place for three months or more, in order for the stretched midpalatine suture (synchondrosis) to be stably replaced with bone structure.
Further, orthodontic expanders are custom fit to the upper palate of a patient with the legs soldered to the expander. Occasionally, unexpected position adjustments of the orthodontic expander are required. The particular orthodontic expander must be removed and discarded. Orthodontic expanders are also typically discarded upon completion of treatment.
Accordingly, there is a need in the art for orthodontic expanders that have any one (or more) of the improved operational features of locking in-place to resist slippage during treatment, providing directional and adjustment indicators that facilitate tracking of treatment with periodic adjustments, restricting apparatus separation, and facilitating economical treatment by not having to discard the expander after use. It is to such independent operating features that the present invention is directed.